It’s been about 21 months since California lawmakers passed Senate Bill 4 and began the process of regulating hydraulic fracturing (fracking). Step one was getting a picture of the fracking landscape, because no one really knew where the new oil and gas well-stimulation techniques, which used dangerous chemicals, were being deployed.

That independent report (pdf), from the California Council on Science and Technology and Lawrence Berkeley National Laboratory, came out in January. It found that around half of new wells drilled in the last decade were fracked. Fracking was found in 96 of California’s 500 oil fields, producing around one-fifth of the state’s oil. Between 125 and 175 new wells out of 300 drilled each month, on average, are fracked. Almost all the fracked wells are in four Kern County oil fields.

Now they have released a second report (pdf), identifying how “stimulation affects water, the atmosphere, seismic activity, wildlife and vegetation, traffic, light and noise levels.”

Or, at least, that was the report’s aim.

Unfortunately, “significant gaps and inconsistencies exist in available voluntary and mandatory data sources, both in terms of duration and completeness of reporting that limit assessment of the impacts of hydraulic fracturing,” the report says.

The uncertainty has prevented the state from getting a handle on potential health and environmental risks from fracking. For instance, “pollutants can be concentrated near production wells and present health hazards to nearby communities” but that hasn’t been studied in California. “California public health studies could determine the magnitude of this issue and the need for any mitigating policies.”

Fracking opponents argue there should be a moratorium on its use until “the magnitude” has been determined and perhaps a little mitigation applied.

Until then, as the report points out, toxicity in more than half the chemicals used in fracking is “uninvestigated, unmeasured and unknown. Basic information about how these chemicals would move through the environment does not exist.”

Recycled oil wastewater—a lot is produced during the drilling—is used to irrigate nearby crops, but the report said testing is inadequate. More than half the wastewater is stored in unlined pits, and can leach into the ground. “The hazardous levels of contaminants . . . cannot be ruled out.”

Nearly one-third of the open pits are operating without a proper permit, the report says. Offshore drillers are discharging wastewater directly into the ocean, in violation of Environmental Protection Agency (EPA) regulations. Frackers are using injection wells to pump oil wastewater back into the ground in locations where federally protected aquifers are affected.

All of the chemicals used in fracking should not be in drinking water, the report says. It is not a good thing that acids, solvents and biocides are being spread in the environment, where they present a “significant hazard to aquatic species and other wildlife, particularly when released into surface water.”

The oil industry said it was buoyed by the report’s findings because widespread specific harms, like contaminated groundwater, were not found. Jane Long, the report's co-lead, told the Los Angeles Times there was a good reason for that.

“We think the fact that we haven't looked for it is an issue,” she said. “You can't find what you don't look for.”